KR101639743B1 - Stretched foam plastic molded article having metallic appearance - Google Patents

Abstract

The present invention provides an expanded molded article such as a bottle having a metallic color, in particular a gold or silver color, without using expensive pigments such as expensive metal powder pigments or scaly pigments. The foamed plastic molded article is formed in at least a part of a foamed region in which the foamed cell 1 is embedded. The foamed cell has a maximum thickness of 30 mu m or less in a vertical section along the maximum stretching direction of the molded article, Foamed plastic skin layer 5 is formed on the outer surface of the foamed region in which the foamed cells are not distributed. The molded article is further characterized in that a non-glossy pigment different from a glossy pigment represented by a scaly pigment as a coloring agent is blended as a coloring agent, and the foamed region of the molded article has a metallic color.

Description

STRETCHED FOAM PLASTIC MOLDED ARTICLE HAVING METALIC APPEARANCE BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an elongated foamed plastic molded article having a metallic color appearance, and more particularly to a stretched foamed plastic bottle having at least a trunk portion as a foaming region and having a metal color (in particular, gold or silver) .

At present, polyester containers typified by polyethylene terephthalate (PET) have excellent properties such as transparency, heat resistance and gas barrier properties and are widely used for various purposes.

On the other hand, in recent years, reuse of resources has been strongly required, and a container having been used up for such a polyester container has been recovered to be reused for various purposes as a recycle resin.

However, the content contained in the packaging container is easily deteriorated by light, for example, any kind of beverage, medicines, cosmetics and the like may be formed in a non-transparent container molded using a resin composition blended with a coloring agent such as pigment Lt; / RTI > The combination of colorants is not desirable in that such opaque containers are reusable resources. Therefore, from the viewpoint of imparting light-shielding property (opacity) without mixing a coloring agent, the present applicant first proposed a foam bottle in which a container wall is foamed by using a microcellular technique (see, for example, Patent Documents 1 to 3).

Japanese Patent Application No. 2007-022554 Japanese Patent Application No. 2007-320082 Japan National Agency 2009-262366

As described above, the so-called foam bottle was developed on the premise that no coloring agent is added, and color inspection for a foam bottle containing a coloring agent is rarely performed.

The inventors of the present invention conducted further experiments on such a foam bottle and found that when a foam bottle using a microcellular technique is prepared by blending a colorant, a gloss pigment represented by an expensive scaly pigment It is possible to obtain a foam bottle having a metallic color, in particular, a golden or silver appearance.

Accordingly, an object of the present invention is to provide an expanded molded article such as a bottle having a metallic color, in particular a gold or silver color, without using an expensive glossy pigment or scaly pigment.

According to the present invention, there is provided a stretched foamed plastic molded article in which a foamed region containing a foamed cell is formed at least in part,

The foamed cell has a flat shape having a maximum thickness of 100 mu m or less as viewed from a vertical section along the maximum stretching direction of the formed body and an average aspect ratio of 4 or more,

A non-foamed plastic skin layer on which the foamed cells are not distributed is formed on an outer surface of the foamed region,

The molded article is characterized in that, as a coloring agent, a non-glossy pigment is blended as a coloring agent, and a foamed region of the molded article has a metallic color.

In the stretched foamed plastic molded article of the present invention

(1) the plastic skin layer has a thickness of 1 to 50 탆,

(2) As the coloring agent, orange-green-based pigments are used, and gold-

(3) a black pigment is used as the coloring agent, and silver,

(4) It is preferable that the container has a bottle shape, and at least the body of the bottle is the foamed area.

The most prominent feature of the stretched foamed plastic molded article of the present invention is that since many foam cells having a minute flat shape are formed using microcellular technology, even though a glossy pigment is not used as a coloring agent but a usual cheap unsharp pigment is used as a coloring agent And the appearance of metallic color is obtained even though a special film for emitting metal color such as a metal vapor deposition film is not formed on the surface. This makes it possible to enhance the decorative property of the stretch-expanded plastic molded article at a very low cost, thereby improving the value of the product.

In addition, the microcellular bubbling is a technique of impregnating a resin with an inert gas as a foaming agent and growing the gas with bubbles to form a foamed cell. The foamed cell is small and uniformly distributed over the entire surface, Further, there is an advantage that the physical properties such as the strength due to the foamed cell are lowered.

Particularly, in the present invention, a drawn or foamed plastic molded article having an appearance of gold or silver can be obtained by suitably selecting a coloring agent to be used under the condition that a non-glossy pigment different from the gloss pigment such as scaly pigment is used as a coloring agent. Such an embodiment can maximize edibility and is an optimal embodiment in the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing a side cross-section along the maximum stretching direction in the foamed region of the oriented, stretch-molded plastic molded article of the present invention.
Fig. 2 is a view showing the shape of a bottle, which is a representative example of the drawn and foamed plastic molded article of the present invention.
Fig. 3 is a cross-sectional view of a preform used in the production of the drawn and stretched plastic molded article of the present invention in a foamed region.
Fig. 4 is a view showing a form of a preform for a container which is molded for producing the bottle of Fig. 2;

1 showing a cross section (vertical cross section along the maximum stretching direction) of a foamed plastic molded article of the present invention in a foam region, in a foamed region of a molded article shown as a whole by 10, a plurality of flat foam cells 1 . That is, since the plastic forming the matrix 3 is stretched in the foam cell 1, all of the foam cells 1 are flattened so that the maximum stretching direction becomes the longest.

In general, many metal powder pigments such as copper powder, aluminum powder, zinc powder, gold powder, and silver powder, scaly flakes such as mica, scaly titanium, and scaly stainless steel, or flake- (Hereinafter, these pigments are sometimes referred to as bright pigments or metallic pigments) which are coated with metal fine particles of cobalt, nickel, titanium or the like (hereinafter sometimes referred to as bright pigments or metallic pigments) One can get an appearance. However, the present invention is not to use such a luster pigment but to color it with a metal color by another coloring agent (non-luster pigment) and the foam cell 1. Therefore, the maximum thickness t of such a flat foam cell 1 is 100 μm or less, preferably 50 μm or less, more preferably 30 μm or less, and the average aspect ratio is 4 or more, preferably 6 to 30 It is necessary that the non-foamed thin plastic skin layer 5 in which the foam cell 1 does not exist is formed on the outer surface.

1, when the maximum length (maximum stretching direction length) of the flat foamed cell 1 is L, L / t (t is the thickness of the cell 1) to be).

That is, the surface of the smooth skin layer 5 (for example, average surface roughness Ra) is imparted with light shielding property by the coloring agent incorporated in the matrix 3 and the foam cell 1 having a small flat shape as described above, (JIS B 0601) of 10 μm or less), the regular reflection, multiple reflection, scattering of light and interference of light in the flat foaming cell 1 are also added, and the nail polish effect The refractive index of the light of the light source is the same) and coloring by the coloring agent are added, resulting in a glossy metallic color appearance.

Particularly, in the present invention, since the amount of bubbles in the foamed cell 1 and the cell diameter (maximum length of the foamed cell 1) is larger, the amount of reflection increases, and therefore the appearance of the molded product 10 becomes brighter, The smaller the cell diameter (the maximum length of the foam cell 1) is, the less the reflected light is, and the appearance of the molded article 10 becomes dark.

In addition, the larger the maximum thickness of the foam cell 1 and the smaller the aspect ratio, the less the regular reflection and the more the diffuse reflection becomes.

In addition, as the thickness of the skin layer 5 is thicker, the nail polish effect is remarkable and the skin color becomes darker. As the thickness of the skin layer 5 becomes thinner, the manicure effect becomes thin and the color becomes light.

Therefore, in the present invention, since the size of the flat foamed cell 1 is specified in a constant range by the average thickness t and the aspect ratio L / t, the bubble count and the thickness of the skin layer 5 The desired metallic color appearance can be obtained by adjusting to the appropriate range according to the color or amount of the colorant.

For example, in order to obtain a metal-colored appearance, if the flat foam cell 1 having the above-mentioned size is formed in a number in which the total light transmittance is 40% or less, particularly 20% or less, good. Here, the total light transmittance may be measured at a wavelength at which the coloring agent to be combined does not exhibit activity, that is, the absorption coefficient a = 0.

The colorant other than the above-mentioned metallic pigment is generally used in an amount of 5 to 0.0005 part by weight, particularly 3 to 0.001 part by weight per 100 parts by weight of the plastic forming the molded article 10 (matrix (3)).

In the present invention, by using the above-described bubble number and the thickness and color of the skin layer 5 and using a non-glossy pigment of an appropriate color as a coloring agent, it is possible to develop a color of gold or silver which has the highest edibility, Which is the greatest advantage of the present invention.

For example, in the present invention, pigments of various colors can be used as colorants other than the above-mentioned gloss pigments, and even when a colorant of any color is used, gloss or reflection due to light scattering, reflection, interference and manicure effect is added A metallic color corresponding to the corresponding color can be exhibited. However, in the case of obtaining a gold color, a non-metallic pigment of an orange-green color system is used. When a silver color is desired, a black color system Of pigments are used.

Specific examples of the non-metallic pigments of an orange to green system include, but are not limited to, the following pigments. Depending on the intended use of the molded article, pigments of such colors may be selected by one kind or a combination of two or more kinds Can be used.

Colored pigment:

Chrome Orange, Molybdenum Orange, Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Indanthrene Brilliant Orange RK, Benzidine Orange G, Indanthrene Brilliant Orange GK.

Red pigment:

Red rhododendron, pyrazolone red, watch red calcium salt, rake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake B, cadmium red, cadmium red, mercury cadmium sulfide, permanent red 4R, , Brilliant Carmine 3B.

Purple pigment:

Manganese violet, fast violet B, methyl violet lake.

Blue pigment:

Cobalt blue, alkali blue lake, victoria blue lake, phthalocyanine blue, nonmetal phthalocyanine blue, phthalocyanine blue part chlorine, fast sky blue, indanthrene blue BC.

Green pigment:

Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake, Final Yellow Green G.

Carbon black is a representative example of a black pigment used for the purpose of silver color. Furthermore, iron-based pigments such as iron oxides are non-glossy pigments, and they may be used as metal powder pigments.

Among the above-mentioned color pigments, in the case of an unfoamed molded article, the a * value is in the range of 20 to -20 and the b * value is in the range of 40 to -5 in the L * a * b * color model And the above-mentioned pigments are preferably used in amounts and combinations in which the L value is 90 or less, particularly 80 to 50, For example, in the bottle described below, it is preferable that the b * value and the L * value in the mouse portion (neck portion) which is a non-foamed region are in the same range as described above.

In order to obtain a clear and clear gold or silver color, the density of the foamed cells 1 in the foam region is in the range of 10 ⁵ to 10 ⁸ / cm 3, and the thickness of the skin layer 5 is in the range of 1 to 20 μm .

In the present invention, by selecting the density (number of cells) of the foam cell 1 and the thickness of the skin layer 5 in addition to the kind and amount of the colorant as described above, a clear and distinct gold or silver color can be expressed.

For example, Pantone color samples No. 871C, 872C, 873C, 874C, 875C, 876C, 8384C, 8385C, 8580C, 8581C, 8582C, 8640C, 8641C, 8642C, 8643C, 8644C, 8645C, 8940C, 8660C, 8960C, The gold color of 8961C can be expressed.

In addition, 877C, 8001C, 8400C, 8401C, 8402C, 8403C, 8404C, 8405C, 8420C, 8421C, 8422C, 8423C, 8424C, 8425C.

The plastic used for forming the above-described stretch foamed plastic molded article 10 (that is, the plastic of the matrix 3) is not particularly limited as far as it is possible to foam by a microcellular impregnated with an inert gas described later, A thermoplastic resin can be used. For example, a random copolymer of? -Olefins such as low density polyethylene, high density polyethylene, polypropylene, poly 1-butene, poly 4-methyl-1-pentene or ethylene, propylene, Olefin resins such as block copolymers and cyclic olefin copolymers; Ethylene / vinyl acetate copolymers such as ethylene / vinyl acetate copolymer, ethylene / vinyl alcohol copolymer and ethylene / vinyl chloride copolymer; Styrenic resins such as polystyrene, acrylonitrile-styrene copolymer, ABS,? -Methylstyrene-styrene copolymer and the like; Vinyl resins such as polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride copolymer, polyacrylic acid methyl and polymethyl methacrylate; Polyamide resins such as nylon 6, nylon 6-6, nylon 6-10, nylon 11, and nylon 12; Polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and copolymer polyesters thereof; Polycarbonate resin; Polyphenylene oxide resin; Biodegradable resins such as polylactic acid; The formed body 10 can be formed. Of course, the molded article 10 may be formed of a mixture of these thermoplastic resins.

In the foamed region, the stretch foamed plastic molded article 10 of the present invention having the aforementioned metal color, particularly gold or silver, is most suitably used as a packaging container, particularly a plastic bottle. That is, a plastic bottle having a metallic color, in particular a gold or silver appearance, can not be produced at low cost and has never been manufactured at all. However, in the present invention, since a plastic bottle can be produced without using expensive metallic pigment, So that the edibility thereof can be maximized.

Fig. 2 shows an example of such a plastic bottle shape. 2, the bottle 60 as a whole is provided with a bottom portion 65 and a body portion 63. A neck portion 61 having a screw portion 61a and a support ring 61b is provided at the upper end of the body portion Respectively. That is, in such a bottle 60, the bottom portion 65 and the trunk portion 63 have a light shielding property as a foam region in which the above-described foam cell 1 is present, and have the metal color described above . On the other hand, the neck portion 61 corresponding to the mouse portion and the vicinity thereof is a non-foamed region, and no foamed cell exists in this region. Therefore, the neck portion 61 has high strength and excellent dimensional stability, and it is possible to firmly and firmly engage the threaded portion 61a with the cap. Also, the support portion 61b can be fastened Can be reliably performed.

Such a plastic bottle 60 is suitably formed of olefin resin or polyester resin, and in particular, a polyester resin such as polyethylene terephthalate is most suitable for molding such a bottle 60.

≪ Production of stretch blow molded plastic article &

In the expanded plastic molded article of the present invention having a metal color, particularly gold or silver, in the foam region, the molding is performed by kneading a coloring agent other than the above-mentioned metallic pigment into plastic, and the size of the foamed cell, the thickness of the skin layer Except that the molding conditions such as the amount of impregnation of the inert gas, the foaming condition, the stretching condition, and the like are adjusted so as to be within the predetermined range, by the known methods proposed by the present applicant (for example, WO2009 / 119549, etc.).

For example, a preform in which an inert gas (e.g., a nitrogen gas or a carbonic acid gas) to be a foaming agent is dissolved is prepared (a step of preparing a gas impregnated preform), and then inert gas is partially released from the surface of the preform (A foaming step). Then, the foam preform thus obtained is finally subjected to stretch forming to selectively stretch the shape of a bottle or the like A foamed plastic molded article can be obtained.

In the process of preparing the gas-impregnated preform, the preform is formed by molding a melt-kneaded product (molding resin composition) of the above-mentioned thermoplastic resin plastics with a predetermined amount of a coloring agent by a known molding means such as extrusion molding, injection molding, However, the impregnation (dissolution of gas) of the inert gas can be performed by placing the molded preform under heating or non-heating under an inert gas atmosphere at a high pressure. The higher the temperature, the lower the dissolution amount of the gas, but the faster the impregnation speed. The lower the temperature, the greater the dissolution amount of the gas, but the impregnation takes time.

It is also possible to obtain a preform impregnated with an inert gas by supplying an inert gas at a high pressure to a molten kneading portion in a molding machine and providing the molding resin composition in which the inert gas is dissolved to the molding such as injection molding. In this case, in order to prevent foaming or the like in an injection molding machine and to obtain a preform having no appearance defects such as a swirl mark, as proposed by the present applicant, for example, in WO2009 / 119549, It is preferable to carry out molding by injecting and filling a resin composition for molding in which an inert gas is dissolved while being wound.

The gas-impregnated preform thus obtained is taken out from the mold under cooling and solidification. In the gas releasing step, the gas-impregnated preform is released under atmospheric pressure (atmospheric pressure) for a predetermined time to release the inert gas from the surface thereof. As a result, a thin skin layer in which the inert gas is not dissolved or the inert gas concentration is lowered is formed in the surface layer portion of the preform, and the skin layer corresponds to the non-foamed plastic skin layer 5 in the above- , And the thickness of the skin layer 5 can be adjusted by the opening time at this time (substantially the time until the next heating foaming is carried out). That is, if the opening time is long, the thickness of the skin layer 5 becomes thick, and the shorter the opening time, the thinner the skin layer 5 becomes.

Since the skin layer 5 may be formed only on the outer surface of the portion to be the foam region and is not deliberately formed over the entirety of the preform, only the portion to be the foam region is exposed to the atmosphere and the other portion is not exposed to the atmosphere The gas may be selectively discharged only to the outer surface of the portion to be the foam region.

In the foaming step subsequent to the above-mentioned gas discharge, a portion serving as a foaming region of the formed body 10 is selectively heated to generate and grow a cell by the expansion of the inert gas, thereby foaming. The heating temperature for foaming is not less than the glass transition point (Tg) of the resin but is required to be less than the melting point of the resin in order to prevent thermal deformation of the preform. As the heating temperature is high and the heating time is long, a large number of cells are formed. Therefore, the cell density and the cell size can be adjusted by using this.

Thus, a foamed preform having a foamed region in which the foamed cells are distributed is obtained. As shown in Fig. 3, a plurality of foam cells 1a are formed in the foamed region of the foamed preform, and a non-foamed layer 5a corresponding to the skin layer 5 finally obtained is formed on the outer face side.

As understood from Fig. 3, since the foamed preform is not drawn and formed, the foamed cell 1a is almost spherical and not flat. Therefore, in the foamed region of the foamed preform, the cell becomes spherical and diffuse, so that it becomes a whitish color, and it does not reach the metallic color due to lack of gloss.

In the present invention, the above-described molded preform is stretched to obtain the molded article 10 having the above-described foam cells 1 having an average thickness (t) and a flat shape of an aspect ratio. Particularly, the appropriate foamed preform in adjusting the melting aforementioned gas amount and the firing conditions (heating temperature) in, for example, the cell density of the foamed cells (1a), a spherical degree 1 × 10 ⁵ to 1 × 10 ⁸ cells / ㎤ and also It is preferable to set the average diameter (circle equivalent diameter) to be about 5 to 50 mu m, and further to set the total light transmittance at this time to 30% or less. That is, by subjecting such a foamed preform to the following stretch forming, a stretched expanded molded article 10 having gold or silver color can be obtained.

The heating for foaming is selectively performed on a portion which becomes a foaming region by blowing hot air, external heating by an infrared heater, immersion in an oil bath, or the like.

For example, FIG. 4 shows the shape of a preform for obtaining the foam bottle 60 shown in FIG. 2. The preform 50 has a test tube as a whole, and a screw 51a and a support ring And a body portion 53 and a bottom portion 55 are formed below the neck portion 51. The body portion 53 and the bottom portion 55 are formed on the neck portion 51. [ 2, since the neck portion 61 provided with the screw 61a and the support ring 61b is a non-foamed region, the neck portion 51 of the preform 50 is also made non- And the body portion 53 and the bottom portion 55 serve as a foam region. By the above-described selective heating, the aforementioned foamed cell 1a is formed.

Of course, when the whole of the molded body 10 is used as a foamed region, the entire foamed preform can be heated.

The stretch molding to be performed on the above-mentioned foamed preform is carried out by a method known per se. For example, a blow molding process in which the preform is heated to a temperature not lower than the glass transition temperature of the resin and lower than the melting point, And stretched by molding or the like to obtain the intended oriented expanded-molded article 10.

That is, in the case of producing a bottle of the type shown in Fig. 2, the test tube-shaped foamed preform shown in Fig. 4 is prepared and provided for blow molding. In the case of producing a cup- A sheet-like foamed preform (the central portion corresponding to the bottom and the body portion becomes the foamed region) may be formed by plug assist molding or the like.

The stretching may be performed in accordance with the diameter or the cell density of the foamed cell 1a in the foamed preform such that the thickness t of the foamed cell 1 or the aspect ratio in the cross section along the maximum stretching direction is in the above- Is carried out at a magnification. For example, in the blow molding which is stretched in the biaxial direction in the axial direction (height direction) and the circumferential direction, the axial direction is generally the maximum stretching direction, and the stretch magnification in this direction is adjusted, It is sufficient to form the foamed cell 1 having a flat shape having an aspect ratio and to form a skin layer 5 having an appropriate thickness. In the plug assist molding or the like in which the stretching is performed in the uniaxial direction only in the axial direction, the stretching in this direction becomes the maximum stretching direction, so that the foam cell 1 and the skin layer 5 having the above- The stretching ratio is adjusted and stretching is performed.

Although the foamed stretched plastic molded article of the present invention (for example, bottle, film, sheet, injection molded article, etc.) obtained as described above is not blended with an expensive luster pigment and a low-cost uneven luster pigment is used as a colorant, The foamed region has a metallic color and high edibility. Especially, the bottle with gold or silver color has high quality and it is supposed to have maximized edibility. Of course, since it has light shielding property, it is effectively applied to accommodation of contents causing deterioration due to light, and is excellent in light weight and heat insulating property by the formation of foam cells.

Example

The present invention will be described by the following experimental examples. Further, the present invention is applicable to the entire foamed and stretched plastic molded article, and is not limited to the following examples.

≪ Example 1 >

3 parts by weight of a colored masterbatch for brown PET resin consisting of red and green organic pigments were dry-mixed and 100 parts by weight of PET resin for bottle (intrinsic viscosity: 0.84 dl / g) were supplied to an injection molding machine.

In the middle of the heating cylinder of the injection molding machine, 0.15 wt% of nitrogen gas was supplied and kneaded with PET resin to dissolve. In order to suppress foaming in the mold, the inside of the mold was pressurized in advance with air (the pressure in the mold was 5 MPa), and the degree of the holding pressure was adjusted so as not to foam (the sealing pressure was 60 MPa and the injection holding time was 22 seconds) Was injected into a mold and cooled and solidified to obtain a test tube-shaped preform for a container. The preform is impregnated with gas but is in a substantially non-foamed state.

The preforms were brown, the foam cells were invisible, and the weight reduction ratio was 0% as compared with the case where foam gas was not added.

Subsequently, the preform body except for the mouth part was heated by an infrared heater to foam, and immediately blow-molded to obtain a foam bottle having an inner volume of about 500 ml.

All of the obtained bottles except for the mouth part had a golden gloss and had excellent appearance and concealability. Compared to the pantone color samples, the color was 8385C.

A cross section perpendicular to the container vertical direction of the bottle body was observed with an operating electron microscope (SEM), and a large number of fine flat cells were observed. The maximum thickness of the bubbles was 32 mu m, the average aspect ratio was 11.2, The surface layer had a skin layer having no bubbles at all, and its thickness was 2 mu m.

A portion of the body of the bottle was cut out and subjected to a one-night (ash) treatment in an electric furnace set at 550 ° C. The residues were 10 ppm or less, and a metal powder pigment and a scaly pigment It was confirmed that there was no pigment residue.

≪ Comparative Example 1 &

A bottle was molded in the same manner as in Example 1, except that nitrogen gas was not added in the heating tube of the injection molding machine in Example 1. The bottle obtained was transparent brown, bubbles were not produced, and concealability and gloss were inferior, and it did not reach the metallic color.

≪ Example 2 >

A bottle was produced in the same manner as in Example 1 except that the blow molding was carried out after the passage of time for one week after the preform was formed in Example 1.

All of the obtained bottles except for the mouth part had a golden gloss and had excellent appearance and concealability. Compared to the Pantone color samples, the color was 8642C. SEM showed that the maximum thickness of the bubble was 28 mu m, the average aspect ratio was 10.9, and the thickness of the skin layer was 19 mu m.

≪ Example 3 >

Bottle molding was carried out in the same manner as in Example 1 except that the amount of the colored masterbatch in Example 1 was changed to 1 part by weight.

The obtained bottle had a bright golden luster throughout the container except for the mouse part, and had excellent appearance and concealability. Compared to the pantone color samples, it had a color of 467C. SEM showed that the maximum thickness of the bubble was 27 mu m, the average aspect ratio was 11.2, and the thickness of the skin layer was 3 mu m.

<Example 4>

A bottle was molded in the same manner as in Example 1 except that the amount of nitrogen gas added in the heating tube of the injection molding machine was 0.12 wt%.

The obtained bottle had a dark golden color throughout the container except for the mouse part, and had an excellent appearance. Compared to the pantone color samples, it had a color of 462C. SEM showed that the maximum thickness of the bubbles was 21 mu m, the average aspect ratio was 10.5, and the thickness of the skin layer was 4 mu m.

&Lt; Comparative Example 2 &

A bottle was molded in the same manner as in Example 1, except that the amount of nitrogen gas added in the heating tube of the injection molding machine was 0.20 wt%. The preforms obtained in the injection stage showed a lot of fine bubbles, and the bottle obtained by blowing had a light yellowish color throughout the container except for the mouse part, and had no glossiness and did not have metallic color. Compared to the pantone color samples, it was 486C in color. SEM showed that the maximum thickness of the bubble was 62 mu m, the average aspect ratio was 10.4, and the thickness of the skin layer was 2 mu m.

&Lt; Comparative Example 3 &

3 parts by weight of the coloring agent for brown PET resin used in Example 1 was dry-blended with 100 parts by weight of PET resin for bottle (intrinsic viscosity: 0.84 dl / g) and supplied to an injection molding machine. In addition, 0.15 wt% of nitrogen gas was supplied in the middle of the heating cylinder of the injection molding machine and kneaded with the PET resin to dissolve. In order to suppress foaming in the mold, the inside of the mold was pressurized with air (pressure in the mold: 5 MPa) , And the degree of the holding pressure was adjusted to adjust the degree of the holding pressure so as not to foam (the holding pressure was 55 MPa and the holding time of the injection holding time was 19 seconds), and the PET resin in which the nitrogen gas was dissolved was injected into the mold and cooled and solidified to obtain an injection molding plate (thickness 1.5 mm). The injection-molded plate is in a substantially non-foamed state although the gas is impregnated.

Subsequently, the obtained injection-molded plate was heated by a hot air blowing oven to obtain a foamed injection-molded plate. The obtained foamed injection-molded plate was ocher-colored and had a hiding power, but was not glossy and did not have metallic color.

The cross section of the molded plate was observed by SEM, and a number of fine spherical cells were formed. The maximum thickness of the bubbles was 47 mu m and the average aspect ratio was 1.1.

&Lt; Example 5 >

0.5 part by weight of black colored PET masterbatch made of carbon black was dry-mixed in 100 parts by weight of PET resin and fed to an injection molding machine in the same manner as in Example 1. 0.13% by weight of nitrogen gas was kneaded and injected To obtain a preform for a container in a substantially non-foamed state. The obtained preform was black, the foam cell was invisible, and the weight reduction ratio was 0%.

Subsequently, blow molding was carried out in the same manner as in Example 1 to obtain a foam bottle having an inner volume of about 500 ml. The obtained bottle had a silver luster all over the container except the mouse part, and had excellent appearance and concealability. Compared to the pantone color samples, it had a color of 8400C.

SEM showed that the maximum thickness of the bubbles was 10 mu m, the average aspect ratio was 8.5, and the thickness of the skin layer was 10 mu m.

&Lt; Example 6 >

Except that the addition amount of the black master batch was changed to 2 parts by weight. Thereafter, in order to remove the gas on the surface layer, a time of one month passed in the atmosphere. After the lapse of time, the bottle was obtained by blowing. The obtained bottle had a silver luster throughout the container except for the mouse part, and had excellent appearance and concealability. Compared to the pantone color samples, the color was 8403C.

Observation of the cross section of the body of the bottle by SEM revealed that the maximum thickness of the bubbles was 5.9 mu m, the average aspect ratio was 9.6, and the thickness of the skin layer was 93 mu m.

1: flat foam cell 3: matrix
5: skin layer 10: stretched foamed plastic molding
t: thickness of foaming cell (1) L: maximum length of foaming cell (1)

Claims (5)

A foamed plastic molding comprising a foaming cell and at least a foam region formed therein,
The foamed cell has a flat shape having a maximum thickness of 50 mu m or less as viewed from a vertical cross-section along the maximum stretching direction of the formed body and an average aspect ratio of 4 or more. The foamed cell has a thickness of 10 ⁵ to 10 ⁸ / cm 3 With a density range,
Wherein a non-foamed plastic skin layer having a thickness of 1 to 20 占 퐉, on which the foamed cells are not distributed, is formed on an outer surface of the foamed region,
Characterized in that the molded article is blended with a non-glossy pigment as a coloring agent, and the foamed region of the molded article has a metallic color. delete The method according to claim 1,
An extruded green colored pigment is used as the coloring agent, and the molded plastic molded article is a gold colored resin. The method according to claim 1,
Wherein a black pigment is used as the coloring agent, and the colored plastic molded article has a silver color. The method according to claim 1,
And the body of the bottle is at least the foam region.

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